This invention relates to a digital frequency converter and finds application in, inter alia, the generation of high speed controllable clocks for use in code correlation arrangements in global positioning systems (GPS) equipments.
For many applications it is desirable to fabricate integrated circuits in current CMOS technology. However, for some circuits such as a multi-bit numerically controlled oscillator (NCO) it is difficult to use CMOS technology for clock frequencies in excess of 20 MHz.
The present invention provides a controllable digital frequency up-converter arrangement which can be made in CMOS and which is functionally the equivalent of an NCO running at a high frequency e.g. 20 MHz or more.